1. Field of the Invention
The present invention relates to a magnetic disc apparatus.
2. Description of Prior Art
A conventional embodiment of the magnetic disc apparatus is disclosed in JP-A-6-68592.
A conventional stator coil used in the magnetic disc apparatus mentioned above is frequently formed by actually winding a metal wire around a rotational axis constituted by a stator coil, or by actually turning the metal wire around another member so as to fit to a casing of a stator. A gap between the adjacent stator coils (or stator cores) is left in a space or is molded by a resin.
At present, a requirement with respect to a compact magnetic disc apparatus is increased, for example, in the case that the magnetic disc apparatus is mounted to a portable device.
In order to fulfill the requirement, it is necessary to manufacture a magnetic disc, a magnetic circuit and the like in a small size.
However, in order to obtain a desired starting torque even when the stator becomes in the small size, the stator coil of a fixed size is required. Accordingly, there is generated a requirement of winding the coil in a high density. In the conventional wire wound system, since a thickness of the wire which can stand against a winding force, and a interval between the wires which can secure an insulating property (an amount shifted by one rotation of the coil) are required, there has been a limit in the winding density.
Then, the inventors of the present invention employs a structure which uses a metal core substrate employing a soft magnetic metal plate for a stator core, forms a stator coil by connecting wire around a core material of the metal core substrate by a through hole and a metal wire with utilizing a wiring process, and fills in a portion between the adjacent stator coils with a resin so as to increased a strength.
However, when actually manufacturing the structure, it has been known that a distortion is generated on the metal core substrate in the periphery of the stator core, and the resin filled in the portion between the adjacent stator coils tends to be peeled off from a portion between the stator coil and the stator core, and has an effect on a turning force of the magnetic disc.